ioToST

Dear libraries at ...,
Shouldn't Control.Monad.ST export ioToST :: IO a -> ST RealWorld a, as
defined in GHC.IO?
Hugs for some reason does not have it, but it would seem trivial to
write, given their stToIO:
stToIO :: ST RealWorld a -> IO a
stToIO (ST f) = IO f
It doesn't look like anyone else even *has* ST...